Beam (nautical)

The beam of a ship is its width at the widest point as measured at the ship's nominal waterline. The beam is a bearing projected at right-angles from the fore and aft line, outwards from the widest part of ship. Beam may also be used to define the maximum width of a ship's hull, or maximum width plus superstructure overhangs.

Generally speaking, the wider the beam of a ship (or boat), the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position.

Typical values

Typical length-to-beam ratios for small sailboats are from 2:1 (dinghies to trailerable sailboats around 20 ft or 6 m) to 5:1 (racing sailboats over 30 ft or 10 m).

Large ships have widely varying beam ratios, some as large as 20:1.

Rowing shells designed for flatwater racing may have length to beam ratios as high as 30:1, while a coracle has a ratio of almost 1:1 – it is nearly circular.

Formula

The beam of many monohull vessels can be calculated using the following formula:

Beam

Beam may refer to:

BEAM

Beam (music)

In musical notation, a beam is a horizontal or diagonal line used to connect multiple consecutive notes (and occasionally rests) in order to indicate rhythmic grouping. Only eighth notes (quavers) or shorter can be beamed. The number of beams is equal to the number of flags that would be present on an un-beamed note.

Grouping

The span of beams indicates the rhythmic grouping, usually determined by the time signature. Therefore, beams do not usually cross bar lines, or major sub-divisions of bars. If notes extend across these divisions, this is indicated with a tie.

In modern practice beams may span across rests in order to make rhythmic groups clearer.

In vocal music, beams were traditionally used only to connect notes sung to the same syllable. In modern practice it is more common to use standard beaming rules, while indicating multi-note syllables with slurs.

Positioning

Notes joined by a beam usually have all the stems pointing in the same direction (up or down). The average pitch of the notes is used to determine the direction – if the average pitch is below the middle staff-line, the stems and beams usually go above the note head, otherwise they go below.

Beam (structure)

A beam is a structural element that is capable of withstanding load primarily by resisting against bending. The bending force induced into the material of the beam as a result of the external loads, own weight, span and external reactions to these loads is called a bending moment. Beams are characterized by their profile (shape of cross-section), their length, and their material.

Beams are traditionally descriptions of building or civil engineering structural elements, but smaller structures such as truck or automobile frames, machine frames, and other mechanical or structural systems contain beam structures that are designed and analyzed in a similar fashion.

Overview

Historically beams were squared timbers but are also metal, stone, or combinations of wood and metal such as a flitch beam. Beams generally carry vertical gravitational forces but can also be used to carry horizontal loads (e.g., loads due to an earthquake or wind or in tension to resist rafter thrust as a tie beam or (usually) compression as a collar beam). The loads carried by a beam are transferred to columns, walls, or girders, which then transfer the force to adjacent structural compression members. In light frame construction joists may rest on beams.